1. Field of the Invention
The present invention is directed generally to a planar optical display, and, more particularly, to a light redirective display panel and a method of making a light redirective display panel.
2. Description of the Background
A thin optical display panel having a plurality of laminated optical waveguides is disclosed in U.S. Pat. No. 5,381,502, herein incorporated by reference, over which the present invention is an improvement. It is known in the art that waveguides may be used to produce an optical panel having an inlet face and an outlet face, and waveguides in a panel may include a transparent core laminated between opposite cladding layers having a lower index of refraction.
A thin display panel formed in this manner may be used in various applications, such as a television video display screen. However, because the screen forms a small acute face angle with the longitudinal axes of the waveguides, the light transmitted by the waveguides has maximum intensity when viewed coaxially, and therefore displays reduced intensity in the normal viewing direction generally perpendicular to the screen. The prior art has attempted to overcome the lowered intensity of light at the screen by frosting the outlet ends of the waveguides defining the screen, thereby diffusing the displayed light. However, frosting of the screen may not adequately increase intensity, and does not resolve the underlying problem of obliquely directed light inherent in the thin panel.
Therefore, the need exists for a thin display panel having increased light intensity at its screen, which light is redirected perpendicular to the screen.
The present invention is directed to an optical display panel which provides improved light intensity at a viewing angle by redirecting light emitting from the viewing screen. The light re-directive display panel includes an inlet face at one end for receiving light, and an outlet screen at an opposite end for displaying the light. The inlet face is defined at one end of a transparent body, which body may be formed by a plurality of waveguides, and the outlet screen is defined at an opposite end of the body and is disposed obliquely with the inlet face. The screen includes light re-directive elements at the outlet screen for re-directing light emitting from the outlet screen.
The present invention is also directed to a method of making a light redirective display panel. The method includes stacking a plurality of glass sheets, each having approximately equivalent light transmissive properties, with a layer of adhesive or epoxy between each sheet, curing the adhesive to form a stack, placing the stack against a saw and cutting the stack, using the saw, at two opposite ends at an angle to form a wedge-shaped panel having an inlet face and an outlet face, and forming at the outlet face a plurality of light redirective elements which direct light incident on the outlet face into a controlled light cone.
The present invention solves problems experienced in the prior art by displaying increased light intensity at the outlet screen through a redirection of light to a direction perpendicular to the outlet screen.